There are no facilities that allow access to the response body. You can, however, differentiate between different error codes by specifying more granular catch event strings. So, for instance, if you have <catch> blocks for "error.badfetch" and "error.badfetch.503", if an HTTP 503 were to be thrown, the latter block would be the one executed as the matching string is longer.

There are no current plans to add this capability but we are always happy to collect feature requests from our customers and have even, on occasion, implemented some of those requests. Thanks for trying to make our products better!